The present invention relates to an electric circuit breaker apparatus for interrupting an electric circuit mounted in a vehicle such as an automobile.
Typically, a vehicle includes lights such as head lights, various types of electric devices including an electric motor for driving wipers, and a storage battery. The electric devices are operated by the power supplied from the storage battery.
When the vehicle is damaged in a car collision, leakage may occur in any of the electric circuits formed by the electric devices and the storage battery. If the vehicle is multifunctional like many cars in these days and has a great number of electric devices and, correspondingly, a great capacity storage battery, undesirable influence by the leakage, such as a failure of electric devices, cannot be ignored.
To solve this problem, Japanese Laid-Open Utility Model Publication No. 56-357 discloses an apparatus for interrupting the connection between a storage battery from an electric device when a car collision occurs. The apparatus has a fuse arranged between the storage battery and the electric device. When the car collision happens, a high current is forcibly supplied to the fuse, thus blowing the fuse. This interrupts the supply of power from the storage battery to the electric device, thus preventing leakage from electric circuits.
Specifically, the portion of the electric circuit closer to the electric device than the portion of the electric circuit interrupted by the fuse does not receive the power. Leakage is thus reliably prevented in the portion of the electric circuit closer to the electric device.
The electric device includes elements that accumulate charge when the electric device is in operation, or specifically when the electric device receives power. The elements include, for example, a capacitor. If a vehicle includes an electric device having such an element and the connection between the storage battery and the electric device is interrupted when a car collision occurs, the potential of a portion of the electric circuit closer to the electric device than the interrupted portion may be maintained excessively high due to the charge accumulated in the electric device. This is an undesirable situation.